Abstract
Monitoring the body condition of free-ranging marine mammals at
different life-history stages is essential to understand their ecology
as they must accumulate sufficient energy reserves for survival and
reproduction. However, assessing body condition in free-ranging marine
mammals is challenging. We cross-validated two independent approaches to
estimate the body condition of humpback whales (Megaptera novaeangliae) at two feeding grounds in Canada and Norway: animal-borne tags (n = 59) and aerial photogrammetry (n
= 55). Whales that had a large length-standardized projected area in
overhead images (i.e. whales looked fatter) had lower estimated tissue
body density (TBD) (greater lipid stores) from tag data. Linking both
measurements in a Bayesian hierarchical model to estimate the true
underlying (hidden) tissue body density (uTBD), we found uTBD was lower
(−3.5 kg m−3) in pregnant females compared to adult males and resting females, while in lactating females it was higher (+6.0 kg m−3). Whales were more negatively buoyant (+5.0 kg m−3)
in Norway than Canada during the early feeding season, possibly owing
to a longer migration from breeding areas. While uTBD decreased over the
feeding season across life-history traits, whale tissues remained
negatively buoyant (1035.3 ± 3.8 kg m−3) in the late feeding
season. This study adds confidence to the effectiveness of these
independent methods to estimate the body condition of free-ranging
whales.
| Original language | English |
|---|---|
| Article number | 20202307 |
| Number of pages | 10 |
| Journal | Proceedings of the Royal Society of London Series B: Biological Sciences |
| Volume | 288 |
| Issue number | 1943 |
| DOIs | |
| Publication status | Published - 27 Jan 2021 |
UN SDGs
This output contributes to the following UN Sustainable Development Goals (SDGs)
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SDG 14 Life Below Water
Keywords
- Tissue body density
- UAV
- Feeding season
- Animal-borne sensor
- Neutral buoyancy
- Cetacean
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Aerial photogrammetry and tag-derived tissue density reveal patterns of lipid-store body condition of humpback whales on their feeding grounds (dataset)
Isojunno, S. (Creator), Martín López, L. M. (Creator), Pomeroy, P. (Creator) & Miller, P. J. (Creator), Figshare, 2021
DOI: 10.6084/m9.figshare.c.5271301.v2
Dataset
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